A type of core-making machine that has been used for many years for making transformer cores is the belt nester. Typically, a belt nester comprises a rotatable arbor about which sections of magnetic strip steel of controlled length are wrapped in superposed relationship as the arbor is rotated, thereby building up a core form that increases in diameter as additional strips are wrapped about those previously wrapped. Wrapping of the strips is effected by use of a flexible belt that encircles the arbor and is driven to cause rotation of the arbor and any strips previously wrapped about the arbor. Strips are fed into the belt nester in such a manner that they enter between the arbor and the encircling belt; and as the belt and arbor move together, each entering strip, or group of strips, is forced by the belt to tightly encircle the arbor or any core form already built up upon the arbor. An example of a belt nester of this type is disclosed in U.S. Pat. No. 3,049,793--Cooper.
Belt nesters of the above type have heretofore been used for making cores that comprise strips of amorphous steel that are wrapped about the rotating arbor. Because the amorphous strips are very thin (e.g., typically only about 1 mil in thickness), it is customary and highly desirable to feed them into the belt nester in groups, each group being at least ten strips in thickness. But one problem that is present when a belt nester is used with groups of amorphous steel strips is that during the nesting process the strips tend to slide about within the group and on the rotatable arbor or on the rotating partially-built up core form, and this is a serious problem because these strips must be precisely and predictably located. To overcome this problem, the assignee of the present invention has covered the strips, just prior to belt nesting, with a volatile liquid such as perchloroethylene that is capable of holding the strips together in the manner required for effective belt nesting. The liquid later evaporates. This, however, is not an entirely satisfactory approach because the perchloroethylene is expensive, is environmentally undesirable, and can produce rust or corrosion problems.